comparative study of the effects of bisoprolol, atenolol and propranolol on plasma lipids and lipoprotein cholesterol in the rat

The effect of short and long term B-adrenergic blockade on plasma lipids and lipoproteins was studied. Results revealed a highly significant increase in plasma triglycerides of rats treated with either bisoprolol [10 mg/kg] or propranolol [30 mg/kg] over a period of 3 and 5 weeks. Atenolol [50 mg/kg], however, did not significantly alter plasma triglyceride levels of rats treated over a period of either 1, 3 or 5 weeks [P >0.05]. Total plasma cholesterol was significantly decreased after treatment of rats with bisoprolol over a period of 1, 3 or 5 weeks. A significant decrease in plasma cholesterol was evident after propranolol treatment when measured after 1 [P <0.001] and 3 [P <0.01] weeks. On the other hand, atenolol significantly decreased plasma cholesterol after 3 and 5 weeks [P <0.001]. The lipoprotein pattern of rats treated with the beta-blockers changed fairly markedly. Thus, atenolol significantly decreased low density lipoprotein [LDL]-cholesterol after 3, 5 weeks [P <0.001] with no significant change in high-density lipoprotein [HDL]-cholesterol. After one week of treatment, however, atenolol significantly increased LDL [P <0.001]. Propranolol, on the other hand, significantly decreased LDL after 3 [P <0.001] and 5 [P <0.01] weeks of daily treatment. However, a significant decrease in HDL was also found after 1 [P <0.001] and 3 [P <0.05] weeks of propranolol treatment. Bisoprolol significantly decreased LDL after 5 weeks of bisoprolol treatment, the highly significant [P <0.001] decrease in LDL was coupled by a significant [P <0.05] increase in the beneficial HDL-cholesterol. The data suggested that both propranolol and atenolol may induce significant, potentially atherogenic changes in lipid metabolism, whereas bisoprolol is relatively advantageous as an alternative in the management of hypertension, especially in subjects with an already atherogenic lipoprotein profile

Effect of sulphonylukea drugs on bile secretion in guinea pigs

The effect of tolbutamide and gliclazide on the flow rate, osmolality and some of the bile constituents was studied in male guinea pigs. The results showed that four weeks oral administration of either tolbutamide or gliclazide, in doses which caused significant hypoglycemia, resulted in a significant increase in bile flow rate, sodium, osmolality. Nonsignificant changes in potassium and bilirubin concentrations were observed. Gliclazide produced a significant decrease, while tolbutamide resulted in a nonsignificant change in hepatic bile cholesterol accompanied by a nonsignificant decrease of phospholipids concentration in both groups. The results suggested that both drugs [specially gliclazide] may have protective effect against the formation of cholesterol gall stones